Ethereum Mainnet Block Oracle System

The Ethereum Mainnet Block Oracle System provides decentralized, permissionless access to Ethereum mainnet block hashes and state roots across multiple chains. Governed by Curve DAO, the system leverages LayerZero relayers and a multi-committer consensus mechanism to securely propagate block data in a trust-minimized manner.

Overview

• MainnetBlockView: A contract on Ethereum mainnet that retrieves block hashes for blocks that are safely aged (greater than 64 and less than 256 blocks old). It defaults to block.number - 65 to avoid reorg risks.
• BlockOracle: A non-mainnet-chain contract (e.g., on Arbitrum, Gnosis, etc.) that accepts block header submissions from trusted committers using a threshold-based consensus mechanism. When the required threshold is met, the block data becomes immutable.
• LayerZero Integration (LZBlockRelay): Contracts deployed on multiple chains that handle cross-chain messaging. LayerZero relayers, configured with multiple DVNs, enable permissionless broadcasts of block data. For the moment, this relayer is sole commiter of blockhashes.

System Operation

1. Block Data Request: Users or relayers trigger a block data request via request_block_hash, which initiates a LayerZero read from MainnetBlockView.

2. Broadcasting: Received block data is sent using broadcast_latest_block across chains through LayerZero’s messaging system.

3. Commitment & Validation: LZ Relayers commit block headers to the BlockOracle. Once a configurable threshold (currently just 1) is reached, the block hash is confirmed and stored permanently.

4. Block Header Submission: RLP encoded block headers can be submitted by anyone to the BlockOracle using submit_block_header.

Use Cases

• State Proofs: Prove mainnet state on sidechains and verify transaction inclusion.

Deployments & Configuration

MainnetBlockView is deployed on Ethereum mainnet: 0xB10CFACE40490D798770FEdd104e0a013eD308a6

Oracles and LZ Relayers are deployed across many chains where Curve Finance is live:

Chain	Oracle Address	Block Relay Address
Arbitrum	0xb10cface0f31830b780C453031d8E803b442e0A4	0xfacefeedcc1a5FDdCa97a20511e6641a5c44370F
Polygon	0xb10cface0f31830b780C453031d8E803b442e0A4	0xfacefeedcc1a5FDdCa97a20511e6641a5c44370F
BSC	0xb10cface0f31830b780C453031d8E803b442e0A4	0xfacefeedcc1a5FDdCa97a20511e6641a5c44370F
Base	0xb10cface0f31830b780C453031d8E803b442e0A4	0xfacefeedcc1a5FDdCa97a20511e6641a5c44370F
Avalanche	0xb10cface0f31830b780C453031d8E803b442e0A4	0xfacefeedcc1a5FDdCa97a20511e6641a5c44370F
Optimism	0xb10cface0f31830b780C453031d8E803b442e0A4	0xfacefeedcc1a5FDdCa97a20511e6641a5c44370F
Fraxtal	0xb10cface0f31830b780C453031d8E803b442e0A4	0xfacefeedcc1a5FDdCa97a20511e6641a5c44370F
Gnosis	0xb10cface0f31830b780C453031d8E803b442e0A4	0xfacefeedcc1a5FDdCa97a20511e6641a5c44370F
Sonic	0xb10cface0f31830b780C453031d8E803b442e0A4	0xfacefeedcc1a5FDdCa97a20511e6641a5c44370F
Ink	0xb10cface0f31830b780C453031d8E803b442e0A4	0xfacefeedcc1a5FDdCa97a20511e6641a5c44370F
Corn	0xb10cface0f31830b780C453031d8E803b442e0A4	0xfacefeedcc1a5FDdCa97a20511e6641a5c44370F

Usage Instructions

To request and broadcast block data, follow the recommended process:

1. Choose a broadcaster chain (e.g., Optimism, Arbitrum, Base).
2. Quote the read fee from the chosen broadcaster chain.
3. Check fees for each target chain by calling quote_broadcast_fees.
4. Calculate the total fees and then complete the broadcast call. You can find example use scripts in scripts/ notebook files.

Future Enhancements

• Expanded Committer Network: Onboard additional trusted committers to further decentralize the consensus process.
• Fee Optimization: Enhance fee management for improved efficiency in cross-chain messaging.

Contact & Support

For additional information or support, please contact the Curve DAO team at [email protected].

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